--- a/src/script.cpp
+++ b/src/script.cpp
@@ -1525,7 +1525,7 @@
 }
 
 
-bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType, CScript scriptPrereq)
+bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType)
 {
     assert(nIn < txTo.vin.size());
     CTxIn& txin = txTo.vin[nIn];
@@ -1534,18 +1534,15 @@
 
     // Leave out the signature from the hash, since a signature can't sign itself.
     // The checksig op will also drop the signatures from its hash.
-    uint256 hash = SignatureHash(scriptPrereq + txout.scriptPubKey, txTo, nIn, nHashType);
+    uint256 hash = SignatureHash(txout.scriptPubKey, txTo, nIn, nHashType);
 
     if (!Solver(keystore, txout.scriptPubKey, hash, nHashType, txin.scriptSig))
         return false;
 
-    txin.scriptSig = scriptPrereq + txin.scriptSig;
-
     // Test solution
     int nUnused = 0;
-    if (scriptPrereq.empty())
-        if (!VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, nUnused, 0, true))
-            return false;
+    if (!VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, nUnused, 0, true))
+        return false;
 
     return true;
 }